There is quality variation in off-the-shelf filament, but after going through about a dozen kilos of ABS and PLA in the past two years I've only found one roll that I hold as 'suspect'.
Right now I'm using a roll that I got from
www.robotdigg.com and it seems to be working just fine. You'll note that robotdigg also has some great deals on steppers and bearings. Their order process isn't a 'one click' process... you actually have to email back and forth a bit before paying over paypal, but I have been happy with the one order that I have placed with them and plan to order more.
A team wanting to save money on filament could always just rip out the original electronics and replace them with a RepRap style control board. I've built a couple RepRap Gen7 boards (for about $30 each, plus another $30 for stepper drivers) and they seem to be working fine in initial testing. After all, FDM 3D printers are basically just four stepper motors and a hot end, plus some limit switches and maybe a heated bed.
Or a team could build their own printer for a couple hundred bucks. Depending on how much printing you are going to do, it might be cheaper to build or buy an open-source machine and use commodity filament.
Jason